这个月的 particulatematter 浓度是多少？请用 json 格式提供数据，其中包括日期、城市、浓度值三个字段。至少提供 2 个不同城市的 4 次测量数据。
user
{
  "data": [
    {
      "date": "2023-10-01",
      "city": "北京",
      "concentration": "75"
    },
    {
      "date": "2023-10-08",
      "city": "北京",
      "concentration": "68"
    },
    {
      "date": "2023-10-15",
      "city": "北京",
      "concentration": "59"
    },
    {
      "date": "2023-10-22",
      "city": "北京",
      "concentration": "63"
    },
    {
      "date": "2023-10-03",
      "city": "上海",
      "concentration": "42"
    },
    {
      "date": "2023-10-10",
      "city": "上海",
      "concentration": "45"
    },
    {
      "date": "2023-10-17",
      "city": "上海",
      "concentration": "49"
    },
    {
      "date": "2023-10-24",
      "city": "上海",
      "concentration": "50"
    }
  ]
}
assistant