The Harmattan is Ghana’s dry, dusty season, usually from about November to March, and it pushes airborne dust up sharply. One study in Accra measured average PM2.5 at 89 µg/m³ during the Harmattan against 23 µg/m³ the rest of the year. To prepare, check your seals, fit good pre-filters, keep spares on site and inspect more often.
What does the data say about Harmattan air quality?
A 2021 peer-reviewed study in Environmental Research Letters found that average PM2.5 in Accra was 89 µg/m³ during the Harmattan and 23 µg/m³ in the non-Harmattan period. For comparison, the World Health Organization’s 2021 guidelines recommend no more than 15 µg/m³ as a 24-hour average and 5 µg/m³ as an annual average.
How does the Harmattan affect equipment?
| Equipment | Effect | What to do |
|---|---|---|
| Air handling units | Pre-filters load quickly and airflow falls | Check pressure drop more often and keep spares |
| Air conditioners | Dirty filters and coils raise energy use | Clean filters more often and service coils before the season |
| HEPA systems | Pre-filter failure exposes costly HEPA filters | Inspect pre-filters and door seals |
| Gas turbines | Dust loads filters and can foul compressors | Monitor pressure drop and plan a change-out before the peak |
| Server and control rooms | Dust settles on sensitive equipment | Keep the room positively pressurised and well filtered |
How should you prepare your building or plant?
- Before the season
Service coils and fans, replace worn seals, and record baseline pressure drop.
- Stock up
Hold spare pre-filters on site. Lead times can lengthen when everyone orders at once.
- During the season
Inspect more often using our replacement guide, and keep doors and windows closed.
- After the season
Inspect final filters and coils, then replace whatever has reached its limit.
Which filters work best against Harmattan dust?
Use filters in stages. A coarse or ePM10 pre-filter takes the heavy dust load so the final filter lasts. An ePM1 final filter then captures the fine particles linked to health effects. For rooms where you cannot change the system, a sized air purifier can help. Gas turbines need a site-specific inlet design.