Identifying the Sources of Winter Air Pollution in Bangkok Part I

To answer these questions, let’s look at the hourly average during the winter.

Note that I plotted normalized data for better comparison.

Normalized average PM 2.

5 for different daysThe air pollution is not better during the weekend.

This may be because the traffic is equally bad (which is true, the traffic is VERY bad on Saturdays).

Or perhaps the high AQI is due to other factors.

First, let’s look closely at how air pollution is related to traffic.

Hourly average of PM2.

5 pollutionThere are some spikes in the morning rush hour (6– 10 am), but not in the evening rush hour.

From this, we can hypothesis that other factors such as temperature and wind play more important roles in determining the air pollution level.

People suffer more in the northWith the start of the monsoon season, the weather in Bangkok will get better, and public attention on this issue will likely fade.

However, without immediate policy measures, the problem will come back again next winter.

In fact, the Bangkok region is not the only place that suffers from particle air pollution.

Below, I show a map of particle pollution in February 2019.

particle pollution map in February 2019The seasonal pollution is not limited to the central region.

While the air pollution in Bangkok peaked in January, the pollution moved to the northern provinces.

In fact, their situation is much worse as judged by the maximum pollution level across the country shown below.

Note that this is a plot of the maximum from monthly averages, to get rid of outliers.

maximum particle pollution in each provinceThe northern provinces, such as Lampang, Chiang Mai, and Chiang Rai, suffer from worse air pollution than Bangkok, but receive much less media attention.

The southern provinces, such as Phuket, Songkhla, and Trang, enjoy good air quality all year round.

In summary, PM 2.

5 pollution has a seasonal trend in Bangkok and the northern provinces, but have only recently received public attention.

During this winter haze, the harmful particle pollution level is high throughout the day, including on weekends.

In Part II of this blog post, I will try to use machine learning to identify the source of the air pollution in Bangkok.

Thank you for reading, and stay tuned for Part II!.If you have any suggestions, please leave your comment below.

I am going to leave you with a gif of the monthly average particle pollution across Thailand.

.. More details

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