Forecast
Air Pollution Forecast from Imperial College London Environmental Research Group
Today
Issued:
29/04/2026 09:09:43
Pollution Band:
Moderate
Details
The current forecast indicates dry conditions with abundant warm sunshine driven by a south easterly air feed.
Back-trajectory analysis suggests this airflow will import existing ozone pollution as the air mass tracks across Central Europe before reaching the UK. This transboundary import will be compounded by local ground-level ozone production, fuelled by rising temperatures and intense solar radiation reacting with both domestic and continental precursor emissions. These photochemical reactions are expected to be particularly pronounced today due to lighter forecast winds, which allow pollutants to accumulate more readily than during recent breezy periods.
Consequently, we anticipate elevated ozone levels consistent with the trends observed over the past several days under similar meteorological conditions.
While particulate levels may also see a rise as the Central European air feed merges with local emissions, they are not currently predicted to reach "Moderate" thresholds.
Air pollution is expected to remain 'Low' for the following pollutants:
PM10 Particulates
PM2.5 Particulates
Nitrogen Dioxide
Sulphur Dioxide
Outlook
Issued:
30/04/2026 09:54:19
Start:
Saturday 2 May
Finish:
end of Saturday 2 May
Pollution Band:
Moderate
Details
The current forecast indicates dry conditions with abundant warm sunshine driven by a south easterly air feed.
Back-trajectory analysis suggests this airflow will import existing ozone pollution as the air mass tracks across Central Europe before reaching the UK. This transboundary import will be compounded by local ground-level ozone production, fuelled by rising temperatures and intense solar radiation reacting with both domestic and continental precursor emissions. These photochemical reactions are expected to be particularly pronounced today due to lighter forecast winds, which allow pollutants to accumulate more readily than during recent breezy periods.
Consequently, we anticipate elevated ozone levels consistent with the trends observed over the past several days under similar meteorological conditions.
PM10 Particulate levels may also see a rise as the Central European air feed merges with local emissions and could reach "Moderate" thresholds, a couple of sites just reached Moderate yesterday.
Air pollution is expected to remain 'Low' for the following pollutants:
PM2.5 Particulates
Nitrogen Dioxide
Sulphur Dioxide
The Ealing 8 monitoring site on Horn Lane, Acton forms part of an investigation of the local PM10 sources at this location. The site is affected by specific local sources of PM10 particulate and it is not representative of other areas within the Borough. Horn Lane will have increased levels of particulate matter that will not be representative of rest of the borough.
How to use the Daily Air Quality Index *
- Step 1: Determine whether you (or your children) are likely to
be at-risk from air pollution. Your doctor may also be able to give you advice.
- Step 2: If you may be at-risk, and are planning strenuous activity
outdoors, check the air pollution forecast.
- Step 3: Use the health messages corresponding to the highest forecast
level of pollution as a guide.
Health Advice
| Air Pollution Banding
|
Value
|
Accompanying health messages for at-risk groups and
the general population
|
| At-risk individuals **
|
General population
|
|
Low
|
1-3
|
Enjoy your usual outdoor activities.
|
Enjoy your usual outdoor activities.
|
|
Moderate
|
4-6
|
Adults and children with lung problems, and adults with heart problems, who
experience symptoms, should consider reducing strenuous
physical activity, particularly outdoors.
|
Enjoy your usual outdoor activities.
|
|
High
|
7-9
|
Adults and children with lung problems, and adults with heart problems, should reduce strenuous physical exertion, particularly outdoors, and particularly
if they experience symptoms. People with asthma may find they need to use their
reliever inhaler more often. Older people should also reduce physical
exertion.
|
Anyone experiencing discomfort such as sore eyes, cough or sore throat should consider reducing activity, particularly outdoors.
|
|
Very High
|
10
|
Adults and children with lung problems, adults with heart problems, and older people,
should avoid strenuous physical activity. People with asthma may
find they need to use their reliever inhaler more often.
|
Reduce physical exertion, particularly outdoors, especially if
you experience symptoms such as cough or sore throat.
|
* Daily Air Quality Index information sourced from
UK-AIR (Air Information Resource) website.
** Adults and children with heart or lung problems are at greater risk of symptoms.
Follow your doctor's usual advice about exercising and managing your condition.
It is possible that very sensitive individuals may experience health effects even
on Low air pollution days.
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