Air Quality Scenario Players
The scenario player is built as an educational tool (see all tools here). The concept is the “pollution-control” game — assigning a value to “accountability” — how much reduction do we require from each spatial authority, to reach a common goal for the airshed. This tool helps visualize not only the change required to reach zone, but also the relative importance of the spatial blocks in the overall air pollution picture (before and after).
In this illustration, each spatial unit is referred to as a zone, but it can equally represent blocks, wards, or districts — whatever spatial segregation the user wants to simulate for the selected air shed. User can enter values only for 2 or 4 zones or all ten zones. We limited the number of zones to 10 — for more flexibility, use the excel file.
The two inputs into the tool are, at the zone level: the average concentration for that spatial unit (ug/m3), and the total population exposed to that concentration (in millions). The sum product of these two inputs is used to calculate the population-weighted concentration for the entire airshed. The pollutant can be anything — PM, SO2, NO2, CO, Ozone, or NH3.
Why we need pop-weighted concentrations (PWC):
PWC = Sum of (Conc × Pop) by zone ÷ Total population
- Exposure assessment must reflect where people are, not just where pollution is — PWC accounts for this distinction. A highly polluted zone with few residents contributes less to total public health burden than a moderately polluted zone with a large population.
- To enable fair prioritization of interventions — PWC allows decision-makers can identify which zones deserve the most urgent attention — not based on peak pollution alone, but on how many people are actually bearing that burden.
- To create a single representative metric for the entire airshed — Averaging raw concentrations across zones ignores spatial inequality in exposure. PWC estimates a representative and actionable summary of total burden.
- To compare before-and-after of policy interventions meaningfully — e.g., when evaluating the impact of an intervention — such as a fuel switch, an industrial relocation, or a traffic restriction — PWC has the potential to highlight whether the reduction actually reached the people who needed it the most, not just whether ambient concentrations reduced somewhere in the airshed.