Near Real-Time Spatial and Temporal Distribution of Traffic Emissions in Bangkok Using Google Maps Application Program Interface

Traffic information from the distance matrix application program interface (API), which is a part of the Google Maps API service, was used to develop a near real-time traffic emissions inventory in Bangkok. The information provided includes distance and traveling time, which can be used to develop an Underwood traffic model for traffic volume estimation. The speed-dependent emission factors, road distance and traffic volume, which were estimated based on the distance matrix API, and fleet composition, were used to estimate carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NOx) and particulate matter (PM) emissions from eight types of vehicles, including passenger cars, motorcycles, pick-ups, taxis, vans, buses, tuk-tuks and trucks. On the weekend, in Bangkok, the traffic released 190 tons/day of CO, 34 tons/day of HC, 55 tons/day of NOx and 3 tons/day of PM. The traffic emissions on a weekday in Bangkok were 209 tons/day of CO, 39 tons/day of HC, 61 tons/day of NOx and 4 tons/day of PM. The spatial and temporal distribution of traffic emissions demonstrate that the area of highest traffic emissions was the center of Bangkok. Therefore, the Google Map API service can be used to develop near real-time traffic emission inventories.