Health Benefits Module

The Health Benefits Module is based on the Air Quality Benefits Assessment Tool (AQBAT) developed by Health Canada (Judek et al., 2012). The module starts by calculating the Baseline Counts (bc_h) for the pre-determined 18 health endpoints used in AQBAT and which are shown in the table below.

HID	Health Endpoint h	Pollutant	Age
1	Acute Exposure Mortality	O3, SO2, NOX	All
2	Acute Respiratory Symptom Days	Acute PM25, O3	All
3	Adult Chronic Bronchitis Cases	Chronic PM25	25+
4	Asthma Symptom Days	Acute PM25, O3	All
5	Cardiac Emergency Room Visits	Acute PM25	All
6	Cardiac Hospital Admissions	Acute PM25	All
7	Child Acute Bronchitis Episodes	Chronic PM25	Under 20
8	Chronic Exposure Mortality	Chronic PM25	30+
9	Elderly Cardiac Hospital Admissions	CO	65+
10	Minor Restricted Activity Days	O3	All
11	Respiratory Emergency Room Visits	Acute PM25, O3	All
12	Respiratory Hospital Admissions	Acute PM25, O3	All
13	Restricted Activity Days	Acute PM25	20+
14	Chronic Exposure Cardiovascular Mortality	Chronic PM25	30+
15	Chronic Exposure Respiratory Mortality	Chronic PM25, O3	30+
16	Chronic Exposure Cerebrovascular Mortality	Chronic PM25	30+
17	Chronic Exposure Ischemic Heart Disease Mortality	Chronic PM25	30+
18	Chronic Exposure Lung Cancer Mortality	Chronic PM25	30+

bc_h is calculated as the product of the r_gi|h values and population size K_gi estimated by SMARTPLANS in each zone i, and then summed over all zones. The result is a vector of 18 bc_h values for the 18 health endpoints:

Next, pollution concentrations for pollutants p are obtained from the estimates generated by the Pollution Concentration Models for both the base case scenario r and alternative scenario a to calculate the average region-wide concentration C_p|r and C_p|a per pollutant p. The module then calculates the Concentration Risk Functions (CRFs) for pollutant p and health endpoint h as the percent excess (PctXS_hp) based on the calculated average concentrations. The CRF is formulated as either a linear or a Poisson function. If the CRF is linear, then:

On the other hand, if the CRF is Poisson, then:

where ω is the threshold per each pollutant and β_CRF are the parameters for each health endpoint specified above.

The Health Benefit Module then calculates the life years gained (LYG_hp) by using the slope values θ_hp:

The gross count (GC_hp) per pollutant p and corresponding health endpoints h for the following pollutants (PM_2.5^Chronic, PM_2.5^Acute, O₃, SO₂, NO_x, and CO) are calculated as follows:

where α_p is a pollution adjustment factor set to 0.4192 for O₃ and 1 for all other pollutants. To avoid double counting, GC_hp values are adjusted for the health endpoints that overlaps with multiple pollutants. That is:

where h^' and p^' pertain to health endpoints and pollutants that overlap with health endpoints h and pollutants p.

The Netted Counts (NC) are then calculated as follows:

Lastly, the Dollar Valuation (DV_hp) for the net count is estimated as follows:

where ρ is the monetary conversion factor value.

RWCModule

Reference

Judek, S., Stieb, D., Jovic, B., Edwards, B., 2012. Air Quality Benefits Assessment Tool (AQBAT) - User Guide. Health Canada - Healthy Environments and Consumer Safety Branch.