bad air quality

We quite often get bad air quality warnings with hot weather. It's been quite bad here today. Earlier this morning the deep mist covered the hills behind us and fingers of blackish/yellowish low lying 'clouds' spread out to the sea. We couldn't see the beach at all. It can't be seen at ground level but from our vantage point it is quite clear. You might think it was a large fire if you hadn't watched it descend from the hills behind us and drift towards the sea. I took this pic around lunchtime and by mid-afternoon it had got lower and darker forming a dark layer just above the sea. It's now mid-afternoon and the beach has only just about cleared although the horizon is still hazy.