Study: EV Fast Charging Stations Emit 3x Fine Particles

Simian Practicalist
Aug 26
3 min read

To those who love electric vehicles (EVs) because it helps “climate change”, there’s good news: a study by Y. Yao et al titled “Fine particulate matter emissions from electric vehicle fast charging stations” posted on 3 June 2025 does not look at the carbon footprint of power generation, so you don’t have to worry about this bursting your bubble regarding that.

Instead, it examines the overlooked issue of fine particulate matter emissions, particularly from Direct Current Fast Charging (DCFC) stations. The main text is about 10 pages so it is a short and easy read.

The existence of DCFC stations is an incentive to purchase EVs because California is stupid enough to push them knowing that the range of some EVs isn’t good and regular charging is too slow. The study attempts to address the environmental and public health concerns regarding these DCFC stations.

Among these 313 outdoor stations, we further narrowed down our selection to those stations that possessed an output exceeding 100 kW for each fast charger and were equipped with at least one stand-alone power cabinet.

Ultimately, the power cabinets of 50 DCFC stations across 47 cities in Los Angeles County were selected, with the nearby EV chargers, 8 gas/petrol stations and 4 park areas as “urban background sampling areas” for comparison. Real-time data for fine particulate matter (PM2.5) was collected from February to May 2024.

Generally, “frequent PM2.5 peaks at the power cabinet, especially between 7:00 am and 9:00 pm” were observed. These peaks typically lag a short period after intense EV charging.

The 24-h mean PM2.5 concentrations at each of the 50 DCFC stations ranged from 7.3 μg m⁻³ to 39.0 μg m⁻³, with “46 % of the sites exceeding the 24-h WHO Global Air Quality Guidelines (AQGs) set at 15 μg m⁻³”.

The researchers considered the claims of diesel being used for power generation at these DCFC stations. The lack of “breakpoints” or step-changes for CO or CO₂ emissions suggests that it is not the case. However, the possibility cannot be ruled out as the measurements were recorded in the vicinity of the DCFC station and a diesel generator could be situated farther away.

The possibility of nucleation due to corona discharge was also considered. The lack of “breakpoints” or step-changes for ambient temperature and O₃ suggests this is not the case.

As for the condensation of glycols as they are commonly used in DCFC cooling systems, the researchers measured particle volatility.

Overall, among all collected particles from the DCFC station, gas station, and urban background site, those from the DCFC station have the lowest percentage of volatile particles (i.e., 10 %).

So, whatever these DCFC stations are emitting, they do not quickly evaporate.

These elevated emissions are “resuspension” of particles, mostly brake and tire wear tracers and dust tracers.

The average two-week PM2.5 concentration at power cabinets was 12.0 ± 3.0 μg m−3, which was 1.22 and 1.56 times the PM2.5 levels at nearby chargers and background sites, respectively. PM2.5 elemental concentrations of brake and tire wear tracers (Ba, Cu, Zn) at the power cabinet were 1.35–1.70 times those at the nearby EV charger, and 2.40–2.96 times those at the background site. Similarly, dust tracers such as Ca, Al, and Fe were 1.65–1.95 times as high at the power cabinet as at the nearby EV charger, and 2.26–3.11 times as high as at the nearby background site.

During the day, the particle size of these emissions decreases as concentration increases; this is plausible as particles accumulate in the cabinet overnight with the larger particles resuspended first when the unit is used in the morning. (See Figure 4c reproduced below.)

In short, these DCFC stations are stirring up the crap that is in the air.