Making Visible the Hidden Health Costs of Air Pollution: Targeted Sampling Using a Mobile In Situ Air Quality Surveyor and Remote Sensing to Map Covid-19 Air Quality Improvements in Communities Downwind of the Ports of Los Angeles and Long Beach

Abstract:

The Ports of Los Angeles and Long Beach are the busiest in the western hemisphere and are situated amid extensive coastal industrial activities include refining, petroleum production, cement production, and water treatment. Heavy-duty diesel trucks (HDDTs) transport the vast majority of containers on area highways, contributing diesel aerosols and volatiles to downwind pollution. The CoVid19 economic damage dramatically reduced US air pollution from traffic, and commercial activities at these ports leading to a partial improvement in downwind community air pollution, while refining and production emissions continued. The pollution profile shifts have significant health implications.

We demonstrate how repeat in situ mobile field data surveys and targeted survey canister sampling provide pollution profiles for sources and in downwind communities. Combined with long-term fixed station air pollution, and satellite and airborne remote sensing can map potential exposure in downwind neighborhoods, guiding epidemiology study development and analysis.

Repeat in situ SISTER (Standard Instrumentation Suite: Truck Enabled for Response) surveys in 2020 during the CoVid19 shutdown in TMOG (Truck MObile trace Gas) Surveyor were conducted in the Port area for comparison with similar summer 2019 data. SISTER measures 13 trace gases, meteorology, and aerosol vertical profile and size spectra, which are real-time visualized to enable targeted sample collection (60+ gases analyzed). The June survey was concurrent with airborne thermal remote sensing by Mako in the port area.

Key findings were dramatic decreases in NOx, significantly different saturated/unsaturated C₁-C₁₁ profiles for port activities, traffic, refining, wastewater, calciner, and downwind neighborhoods, and strong emissions from remaining commercial activities. Inverse plume-models were validated against remote sensing data and fused with sample analysis to derive emission factors for a broad spectrum of trace gases. Forward modeling, validated by comparison with satellite and permanent station data provides exposure maps for assessing potential health implications.