model{
  for(i in 1:30){
    Concentration[i] ~ dnorm(mu[i], tau)
    mu[i] <- beta[1]*I[i] + beta[2]*H[i] + 
             beta[3]*D1[i] + beta[4]*D2[i] + beta[5]*D3[i] +  
             beta[6]*D4[i] + beta[7]*D5[i] + beta[8]*D6[i] +
             beta[9]*D7[i] +beta[10]*D8[i] + beta[11]*D9[i] + beta[12]*D10[i]
  }
  for(i in 1:12){ beta[i] ~ dnorm(0,0.01) }
  tau ~ dgamma(0.01,0.01)
  diff12 <- beta[2] - beta[1]
  diff13 <-   -beta[1] 
  diff23 <-   -beta[2]
}