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Model formulation document

For details on the NY-CHAPPA modeling framework, please see the NY-CHAPPA Model Formulation Document and Arunachalam et al. (2025).

Scenario year

When setting up a NY-CHAPPA v1.0 scenario, the Scenario Year setting determines which data to use for three calculations:

  1. The transported components, either from user-provided data or from base data, used for calculating total PM2.5
  2. The base concentrations, either from user-provided data or from base data, used for calculating changes in total PM2.5 (delta PM2.5)
  3. Built-in population and incidence data used for calculating health and economic impacts due to the changes in total PM2.5

If you provide your own transported components or base concentrations, make sure the Year column in the uploaded data files matches your selected Scenario Year.

Input data formats

All inputs are text-based CSV files.

Users who modify area emissions using Excel need to ensure that the values in the "geoid" column retain the exact census tract or block group IDs. Excel can often save the values in scientific notation, which truncates the geoid, and you may receive an error when uploading if the CSV saved the geoid values with scientific notation. To ensure that the file saves properly, you should highlight the geoid column, and then format the cells and choose Number with 0 decimal places.

Area emissions

For information about the tier1, tier2, and tier3 values supported by NY-CHAPPA v1.0, see Emission tiers.

Name Description Units Type Example
geoid 2010 census tract or block group ID 11- or 12-digit string 36001000100
tier1 Tier 1 code Integer 2
tier2 Tier 2 code Integer 1
tier3 Tier 3 code Integer 99
nh3 Annual NH3 emissions tons/year Numeric >= 0 0.00072700
nox Annual NOx emissions tons/year Numeric >= 0 0.24718159
pm25 Annual PM2.5 emissions tons/year Numeric >= 0 0.10810850
so2 Annual SO2 emissions tons/year Numeric >= 0 1.16766645
voc Annual VOC emissions tons/year Numeric >= 0 0.00363502

Emissions for census tracts larger than 20 square kilometers must be provided at the block group level. Emissions provided at the block group level but modeled at the tract level will be summed as needed.

Airport takeoff and landing emissions

Airport emissions can be modeled at three separate heights (0, 500, and 2000 feet). Use the tier codes to assign emissions for each height, as follows:

Tier 1 Tier 2 Tier 3 Modeling Height
12 3 99 0 feet (0 meters)
12 3 500 500 feet (150 meters)
12 3 2000 2000 feet (600 meters)

Note that tier codes 12_3_500 and 12_3_2000 can only be used with geoids identified as containing an airport. See the file CHAPPA_geoids_with_airports.csv for a list of these geoids in NY-CHAPPA v1.0.

For the large airports in New York City (JFK and LaGuardia), emissions at 2000 feet can be modeled using a special expanded shape. This shape is an 11-by-11 mile square centered at the location of the airport. To use the special shape, set the geoid to 36081971600 (JFK) or 36081933100 (LGA) along with the tier code 12_3_2000.

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Road emissions

Name Description Units Type Example
road_id ID to match to system road network Integer 1
start_longitude Road segment starting longitude degrees Numeric -73.925486
start_latitude Road segment starting latitude degrees Numeric 42.749585
end_longitude Road segment ending longitude degrees Numeric -73.924415
end_latitude Road segment ending latitude degrees Numeric 42.748948
fips FIPS code (used to assign segment to a modeling region) 5-digit string 36001
road_type Road type (informational only) Integer: 2 – 5 (see below for road types) 4
nh3 Annual NH3 emissions tons/year Numeric >= 0 0.02477286
nox Annual NOx emissions tons/year Numeric >= 0 0.11832313
pm25 Annual PM2.5 emissions tons/year Numeric >= 0 0.00407769
so2 Annual SO2 emissions tons/year Numeric >= 0 0.00574676
voc_ld Annual VOC emissions for light duty vehicles tons/year Numeric >= 0 0.00917919
voc_hd Annual VOC emissions for heavy duty vehicles tons/year Numeric >= 0 0.00337424

Road types

VOC emissions are split between light duty and heavy duty vehicles to allow for calculation of SOA emissions using scaling factors from COBRA.

Road segments must match the system road network, as verified by road_id and fips. Adding road segments is not supported in NY-CHAPPA v1.0.

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Point emissions

Name Description Units Type Example
longitude Longitude degrees Numeric -73.874283
latitude Latitude degrees Numeric 42.583249
fips FIPS code (used to assign source to a modeling region) 5-digit string 36001
stkhgt Stack height feet Numeric > 0 54.3684
stkdiam Stack diameter feet Numeric > 0 21.0714
stktemp Stack temperature degrees Fahrenheit Numeric > 0 186.3300
stkflow Stack flow (only used if stack velocity isn’t provided) cubic feet/second Numeric > 0, can be blank if stack velocity is provided
stkvel Stack velocity feet/second Numeric > 0, can be blank if stack flow is provided 19.5200
tier1 Tier 1 code Integer, must be either 1 or 2 2
tier2 Tier 2 code Integer, can be blank
tier3 Tier 3 code Integer, can be blank
nh3 Annual NH3 emissions tons/year Numeric >= 0 0.00000000
nox Annual NOx emissions tons/year Numeric >= 0 0.39520161
pm25 Annual PM2.5 emissions tons/year Numeric >= 0 0.03436395
so2 Annual SO2 emissions tons/year Numeric >= 0 0.00236898
voc Annual VOC emissions tons/year Numeric >= 0 0.02173383

Point sources must match the master list of point sources modeled by NY-CHAPPA v1.0. This matching is done based on coordinates (longitude and latitude) and FIPS code. Adding point sources is not supported in NY-CHAPPA v1.0.

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Transported components

Transported components represent the concentrations produced from emission sources outside the modeling region. These values are estimated using the COBRA model by zeroing out all emissions within the modeling region. See Modeling regions for the lists of counties within each modeling region.

Name Description Units Type Example
fips FIPS code 5-digit string 36001
year Year: 2025, 2030, 2035, 2040, 2045, 2050 Integer 2025
pm25_transport PM2.5 concentration ug/m3 Numeric 1.61468
soa_transport SOA concentration ug/m3 Numeric 1.16215
so4_transport SO4 concentration ug/m3 Numeric 0.32561
nh4_transport NH4 concentration ug/m3 Numeric 0.73899
no3_transport NO3 concentration ug/m3 Numeric 0.99521

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Base concentrations

A base concentrations file can be generated by running a NY-CHAPPA v1.0 scenario and setting the Base Concentrations option to "None; output concentrations only". This allows you to create your own custom baseline concentrations for calculating delta PM2.5 when modeling a scenario.

Name Description Units Type Example
tract 2010 census tract ID 11-digit string 36001000100
year Year: 2025, 2030, 2035, 2040, 2045, 2050 Integer 2025
total_pm25 Total PM2.5 concentration ug/m3 Numeric 8.073350

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Emission tiers

The 14 top level emission tiers (tier 1) are shown below. For a complete list of tiers 2 and 3 that NY-CHAPPA v1.0 supports, please see the spreadsheet CHAPPA_emission_tiers.csv

Tier 1 Code Tier 1 Description
1 Fuel Combustion: Electric Utility
2 Fuel Combustion: Industrial
3 Fuel Combustion: Other
4 Chemical & Allied Product Manufacturing
5 Metals Processing
6 Petroleum & Related Industries
7 Other Industrial Processes
8 Solvent Utilization
9 Storage & Transport
10 Waste Disposal & Recycling
11 Highway Vehicles
12 Off-Highway
13 Natural Resources
14 Miscellaneous

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Modeling regions

Modeling Region Counties
Capital Region 36001, 36021, 36039, 36083, 36091, 36093, 36113, 36115
Central New York 36011, 36023, 36053, 36067, 36075
Mid-Hudson 36027, 36071, 36079, 36105, 36111
Mohawk Valley 36035, 36043, 36057, 36065, 36077, 36095
North Country 36019, 36031, 36033, 36041, 36045, 36049, 36089
NYC / LI / Lower Hudson 36005, 36047, 36059, 36061, 36081, 36085, 36087, 36103, 36119
Southern Tier 36007, 36015, 36017, 36025, 36097, 36101, 36107, 36109
Western New York / Finger Lakes 36003, 36009, 36013, 36029, 36037, 36051, 36055, 36063, 36069, 36073, 36099, 36117, 36121, 36123

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Reporting regions

Reporting Region Counties
Capital Region 36001, 36021, 36039, 36083, 36091, 36093, 36113, 36115
Central New York 36011, 36023, 36053, 36067, 36075
Finger Lakes 36037, 36051, 36055, 36069, 36073, 36099, 36117, 36121, 36123
Hudson Valley 36027, 36071, 36079, 36087, 36105, 36111, 36119
Long Island 36059, 36103
Mohawk Valley 36035, 36043, 36057, 36065, 36077, 36095
New York City 36005, 36047, 36061, 36081, 36085
North Country 36019, 36031, 36033, 36041, 36045, 36049, 36089
Southern Tier 36007, 36015, 36017, 36025, 36097, 36101, 36107, 36109
Western New York 36003, 36009, 36013, 36029, 36063

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Output options

Tract-level results

Changes in tract-level concentrations and the associated health and economic impacts are output when you set the Base Concentrations option to either "Built-in baseline for scenario year" or "Custom; upload concentrations". If you select "None; output concentrations only", the output file will match the format described in Base concentrations.

Note that the Delta PM2.5 value is calculated as Total PM2.5 (PM2.5 calculated from the modeled scenario) - Base PM2.5. When health and economic impacts are calculated, the sign is flipped, so that the results represent incidences avoided and dollars saved. A scenario with lower concentrations than the base will produce negative delta PM2.5 values and positive impact values.

Name Description Units Type Example
Tract 2010 census tract ID 11-digit string 36001000100
Region Reporting region name String Capital Region
DAC Designation Disadvantaged community designation String: DAC, Non DAC
2025 Population Total population in census tract for 2025 Numeric 2234.030259
Year Year: 2025, 2030, 2035, 2040, 2045, 2050 Integer 2025
Delta PM2.5 (ug/m^3) Change in total PM2.5 concentration (Total - Base) ug/m3 Numeric
Total PM2.5 (ug/m^3) Total PM2.5 concentration ug/m3 Numeric
Base PM2.5 (ug/m^3) Base total PM2.5 concentration ug/m3 Numeric
Mortality (low estimate) Numeric
Mortality (high estimate) Numeric
Infant Mortality Numeric
Nonfatal Heart Attacks (low estimate) Numeric
Nonfatal Heart Attacks (high estimate) Numeric
Hospital Admits, All Respiratory Numeric
Hospital Admits, All Respiratory Direct Numeric
Hospital Admits, Asthma Numeric
Hospital Admits, Chronic Lung Disease Numeric
Hospital Admits, Cardio (except heart attacks) Numeric
Acute Bronchitis Numeric
Upper Respiratory Symptoms Numeric
Lower Respiratory Symptoms Numeric
Emergency Room Visits, Asthma Numeric
Minor Restricted Activity Days Numeric
Work Loss Days Numeric
Asthma Exacerbation Numeric
Asthma Exacerbation, Cough Numeric
Asthma Exacerbation, Shortness of Breath Numeric
Asthma Exacerbation, Wheeze Numeric
Total Health Benefits (low estimate) ($) $ Numeric
Total Health Benefits (high estimate) ($) $ Numeric
Mortality (low estimate) ($) $ Numeric
Mortality (high estimate) ($) $ Numeric
Infant Mortality ($) $ Numeric
Nonfatal Heart Attacks (low estimate) ($) $ Numeric
Nonfatal Heart Attacks (high estimate) ($) $ Numeric
Hospital Admits, All Respiratory ($) $ Numeric
Hospital Admits, Cardiovascular ($) $ Numeric
Acute Bronchitis ($) $ Numeric
Upper Respiratory Symptoms ($) $ Numeric
Lower Respiratory Symptoms ($) $ Numeric
Emergency Room Visits, Asthma ($) $ Numeric
Minor Restricted Activity Days ($) $ Numeric
Work Loss Days ($) $ Numeric
Asthma Exacerbation ($) $ Numeric

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Regional aggregation report

In addition to tract-level results, scenario results are available aggregated by reporting region. See Reporting regions for the lists of counties within each reporting region.

Name Description Units Type Example
Region Name of the reporting region String New York City
Total Health Benefits, High, DAC ($) Total health benefits (high estimate) for tracts designated as DAC $ Integer 207,200
Total Health Benefits, High, Non-DAC ($) Total health benefits (high estimate) for tracts designated as Non-DAC $ Integer 117,674
Total Region Health Benefits, High ($) Total health benefits (high estimate) for all tracts $ Integer 324,874
Fraction of Total Health Benefits, High, DAC Fraction of total health benefits (high estimate) for tracts designated as DAC % Integer 64
Fraction of Total Health Benefits, High, Non-DAC Fraction of total health benefits (high estimate) for tracts designated as Non-DAC % Integer 36
Total Health Benefits, Low, DAC ($) Total health benefits (low estimate) for tracts designated as DAC $ Integer 93,382
Total Health Benefits, Low, Non-DAC ($) Total health benefits (low estimate) for tracts designated as Non-DAC $ Integer 52,375
Total Region Health Benefits, Low ($) Total health benefits (low estimate) for all tracts $ Integer 145,757
Fraction of Total Health Benefits, Low, DAC Fraction of total health benefits (low estimate) for tracts designated as DAC % Integer 64
Fraction of Total Health Benefits, Low, Non-DAC Fraction of total health benefits (low estimate) for tracts designated as Non-DAC % Integer 36
Fraction of 2025 Population, DAC Percentage of population in DAC tracts % Integer 49
Fraction of 2025 Population, Non-DAC Percentage of population in Non-DAC tracts % Integer 51

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Data retention policy

As part of our data management and clean-up policy, all inputs uploaded to NY-CHAPPA v1.0 and all results generated from your NY-CHAPPA v1.0 scenario will be kept for 7 days. After this period, the data will be removed. We encourage you to download your results while they are available.

Version updates

NY-CHAPPA v1.0 (20251109)

CHAPPA version 20251028

CHAPPA version 20250803

CHAPPA version 20250717

CHAPPA verion 20250626

CHAPPA version 20250606

CHAPPA version 20250319

CHAPPA version 20250313

CHAPPA version 20250218

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